1. Field of the Invention
This invention relates to couplings for tubes and other fluid handling components.
2. Prior Art
It is known (see for example U.S. Pat. Nos. 4,005,883 and 4,178,023) to form a coupling of two components, one of these components having a body portion with a bore having a taper to give a decreasing diameter towards an entry end of the bore, a collet having resilient arms being located in this bore, and the second component having a tube adapted for insertion into a said collet through the entry end to be gripped thereby, the tapered bore causing the grip to be tightened if the second component is pulled in the outward direction from the bore in the first component.
Such a construction enables a coupling to be effected, e.g. a tube secured in a fluid-tight manner to a first component, quickly and easily simply by inserting the tube in the first component.
In such constructions heretofore, the tube has been releasable from the first component by pressing the collet inwardly into the first component. There are however many requirements in which a tube has to be secured to another component to form a fluid-tight path through the coupling and in which it is required to prevent any uncoupling of the assembly.
It is an object of the present invention to provide a construction permitting the rapid assembly together of tubes or other fluid handling components which does not require the use of any tools but which forms a permanent and non-releasable coupling.
According to this invention, a coupling is formed of two components, one component having a body portion with a bore having a taper to give a decreasing diameter towards an entry end of the bore and with a collet having resilient arms in the bore and the second component having a tube adapted for insertion into said collet through the entry end to be gripped thereby, the tapered bore causing the grip to be tightened if the second component is pulled in the outward direction from the bore in the first component, the collet having a portion protruding out of the first component through said entry end of the bore and the second component having a portion extending around the protruding end of the collet and the two components having surfaces which abut to prevent the collet being pressed inwardly into the bore in the first component by moving the two components towards one another.
The collet conveniently has a circular head or flange lying outside the bore in the first component, which head or flange forms a rigid support for the collet arms and, in this case, the second component may have an annular recess in an end face to receive the head or flange on the collet.
With the construction described above, the tube on the second component can be inserted into the collet in the bore of the first component and is gripped thereby. Any attempt to pull the components apart results in the grip tightening. In this construction, it is not possible to obtain access to the outer end of the collet to press it into or hold it inwardly in the first component to release the collet grip on said tube.
The two components are conveniently made of rigid or semi-rigid plastics material. It will be noted that the first component can be used, on its own, as a coupling to receive a tube and, in this case it forms a releasable coupling. However the co-operative use of the two components forms an assembly in which the components can be joined simply by putting them together with the tube on the second component passing into the collet; they cannot then be pulled apart.